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MICRO FLUIDICS | ARTICLE


<< Figure 1: Te powderblasting process. >>


Cleanroom Processes for Micro Fluidics Near the German border in the east of The


Netherlands you will find a micro and nano fluidic cluster around the University of Twente in


Enschede. Its campus houses the High Tech Factory and the Nanolab. The High Tech factory offers cleanrooms and lab facilities for rent for


companies and start-ups. The Nanolab facilities are part of Mesa+ research Institute, one of the world’s largest nano technology research


institutes; and it’s the largest research institute in this field in the Netherlands. This is the place


where Micronit Microfluidics has its roots and has become a fully-fledged R&D and manufacturing facility in the field of micro fluidics over the last decade. In its 300m2


cleanroom, equipped with


state-of-the-art micro machinery, processes like wet-etching, aligning, metrology, scribing and


dicing take place. These processes are performed mainly on glass wafers (square and round) in


diameters/dimensions of 100, 150 and 200 mm for both the micro fluidics and MEMS markets. The


combination of these cleanroom processes and the knowledge of the behaviour of micro fluidics


makes it possible for Micronit Microfluidics to provide a total solution.


by WILLY-AN SILVIUS AND MICHA MULDER


Powderblasting Powderblasting is a flexible, cost-effective and accurate technique to create fluidic channels and interconnections, because of the use of a lithographic mask position accuracy is very good, within 2 µm. The feature size accuracy is about 25 µm. Further powderblasting makes it possible to be flexible on the layout and design of the holes and channels.


The first step in this process is to transfer the design of the channels and holes onto the glass by means of photolithography: a photoresist film is laminated on the glass and the mask with the design is positioned above the film. The film is then illuminated with UV light through the mask. Illuminated areas will be removed from the glass during development. During the exposure of the wafer to the powder the areas not covered by film are etched, while the covered areas deflect the powder. The etch rate and depth can be controlled by controlling the time and particle speed.


With sophisticated powderblasting equipment the glass substrate with the developed film can be processed. By processing by lithography and powderblasting, the complexity of the design is irrelevant (when the design meets the tolerances) and only one mask is needed when processing more substrates.


After the powderblasting process the substrate features wells and channels in different shapes and depths. Shaped wells can be round, rectangular or triangular. The sides of the wells will not be


30 | commercial micro manufacturing international Vol 7 No.3


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